text: /*
   * TI OMAP4 ISS V4L2 Driver - Generic video node
   *
   * Copyright (C) 2012 Texas Instruments, Inc.
   *
   * Author: Sergio Aguirre <sergio.a.aguirre@gmail.com>
   *
   * This program is free software; you can redistribute it and/or modify
   * it under the terms of the GNU General Public License as published by
   * the Free Software Foundation; either version 2 of the License, or
   * (at your option) any later version.
   */
  
  #include <asm/cacheflush.h>
  #include <linux/clk.h>
  #include <linux/mm.h>
  #include <linux/pagemap.h>
  #include <linux/sched.h>
  #include <linux/slab.h>
  #include <linux/vmalloc.h>
  #include <linux/module.h>
  #include <media/v4l2-dev.h>
  #include <media/v4l2-ioctl.h>
  
  #include "iss_video.h"
  #include "iss.h"
  
  static unsigned debug;
  module_param(debug, uint, 0644);
  MODULE_PARM_DESC(debug, "activates debug info");
  
  /* -----------------------------------------------------------------------------
   * Helper functions
   */
  
  static struct iss_format_info formats[] = {
  	{ MEDIA_BUS_FMT_Y8_1X8, MEDIA_BUS_FMT_Y8_1X8,
  	  MEDIA_BUS_FMT_Y8_1X8, MEDIA_BUS_FMT_Y8_1X8,
  	  V4L2_PIX_FMT_GREY, 8, "Greyscale 8 bpp", },
  	{ MEDIA_BUS_FMT_Y10_1X10, MEDIA_BUS_FMT_Y10_1X10,
  	  MEDIA_BUS_FMT_Y10_1X10, MEDIA_BUS_FMT_Y8_1X8,
  	  V4L2_PIX_FMT_Y10, 10, "Greyscale 10 bpp", },
  	{ MEDIA_BUS_FMT_Y12_1X12, MEDIA_BUS_FMT_Y10_1X10,
  	  MEDIA_BUS_FMT_Y12_1X12, MEDIA_BUS_FMT_Y8_1X8,
  	  V4L2_PIX_FMT_Y12, 12, "Greyscale 12 bpp", },
  	{ MEDIA_BUS_FMT_SBGGR8_1X8, MEDIA_BUS_FMT_SBGGR8_1X8,
  	  MEDIA_BUS_FMT_SBGGR8_1X8, MEDIA_BUS_FMT_SBGGR8_1X8,
  	  V4L2_PIX_FMT_SBGGR8, 8, "BGGR Bayer 8 bpp", },
  	{ MEDIA_BUS_FMT_SGBRG8_1X8, MEDIA_BUS_FMT_SGBRG8_1X8,
  	  MEDIA_BUS_FMT_SGBRG8_1X8, MEDIA_BUS_FMT_SGBRG8_1X8,
  	  V4L2_PIX_FMT_SGBRG8, 8, "GBRG Bayer 8 bpp", },
  	{ MEDIA_BUS_FMT_SGRBG8_1X8, MEDIA_BUS_FMT_SGRBG8_1X8,
  	  MEDIA_BUS_FMT_SGRBG8_1X8, MEDIA_BUS_FMT_SGRBG8_1X8,
  	  V4L2_PIX_FMT_SGRBG8, 8, "GRBG Bayer 8 bpp", },
  	{ MEDIA_BUS_FMT_SRGGB8_1X8, MEDIA_BUS_FMT_SRGGB8_1X8,
  	  MEDIA_BUS_FMT_SRGGB8_1X8, MEDIA_BUS_FMT_SRGGB8_1X8,
  	  V4L2_PIX_FMT_SRGGB8, 8, "RGGB Bayer 8 bpp", },
  	{ MEDIA_BUS_FMT_SGRBG10_DPCM8_1X8, MEDIA_BUS_FMT_SGRBG10_DPCM8_1X8,
  	  MEDIA_BUS_FMT_SGRBG10_1X10, 0,
  	  V4L2_PIX_FMT_SGRBG10DPCM8, 8, "GRBG Bayer 10 bpp DPCM8",  },
  	{ MEDIA_BUS_FMT_SBGGR10_1X10, MEDIA_BUS_FMT_SBGGR10_1X10,
  	  MEDIA_BUS_FMT_SBGGR10_1X10, MEDIA_BUS_FMT_SBGGR8_1X8,
  	  V4L2_PIX_FMT_SBGGR10, 10, "BGGR Bayer 10 bpp", },
  	{ MEDIA_BUS_FMT_SGBRG10_1X10, MEDIA_BUS_FMT_SGBRG10_1X10,
  	  MEDIA_BUS_FMT_SGBRG10_1X10, MEDIA_BUS_FMT_SGBRG8_1X8,
  	  V4L2_PIX_FMT_SGBRG10, 10, "GBRG Bayer 10 bpp", },
  	{ MEDIA_BUS_FMT_SGRBG10_1X10, MEDIA_BUS_FMT_SGRBG10_1X10,
  	  MEDIA_BUS_FMT_SGRBG10_1X10, MEDIA_BUS_FMT_SGRBG8_1X8,
  	  V4L2_PIX_FMT_SGRBG10, 10, "GRBG Bayer 10 bpp", },
  	{ MEDIA_BUS_FMT_SRGGB10_1X10, MEDIA_BUS_FMT_SRGGB10_1X10,
  	  MEDIA_BUS_FMT_SRGGB10_1X10, MEDIA_BUS_FMT_SRGGB8_1X8,
  	  V4L2_PIX_FMT_SRGGB10, 10, "RGGB Bayer 10 bpp", },
  	{ MEDIA_BUS_FMT_SBGGR12_1X12, MEDIA_BUS_FMT_SBGGR10_1X10,
  	  MEDIA_BUS_FMT_SBGGR12_1X12, MEDIA_BUS_FMT_SBGGR8_1X8,
  	  V4L2_PIX_FMT_SBGGR12, 12, "BGGR Bayer 12 bpp", },
  	{ MEDIA_BUS_FMT_SGBRG12_1X12, MEDIA_BUS_FMT_SGBRG10_1X10,
  	  MEDIA_BUS_FMT_SGBRG12_1X12, MEDIA_BUS_FMT_SGBRG8_1X8,
  	  V4L2_PIX_FMT_SGBRG12, 12, "GBRG Bayer 12 bpp", },
  	{ MEDIA_BUS_FMT_SGRBG12_1X12, MEDIA_BUS_FMT_SGRBG10_1X10,
  	  MEDIA_BUS_FMT_SGRBG12_1X12, MEDIA_BUS_FMT_SGRBG8_1X8,
  	  V4L2_PIX_FMT_SGRBG12, 12, "GRBG Bayer 12 bpp", },
  	{ MEDIA_BUS_FMT_SRGGB12_1X12, MEDIA_BUS_FMT_SRGGB10_1X10,
  	  MEDIA_BUS_FMT_SRGGB12_1X12, MEDIA_BUS_FMT_SRGGB8_1X8,
  	  V4L2_PIX_FMT_SRGGB12, 12, "RGGB Bayer 12 bpp", },
  	{ MEDIA_BUS_FMT_UYVY8_1X16, MEDIA_BUS_FMT_UYVY8_1X16,
  	  MEDIA_BUS_FMT_UYVY8_1X16, 0,
  	  V4L2_PIX_FMT_UYVY, 16, "YUV 4:2:2 (UYVY)", },
  	{ MEDIA_BUS_FMT_YUYV8_1X16, MEDIA_BUS_FMT_YUYV8_1X16,
  	  MEDIA_BUS_FMT_YUYV8_1X16, 0,
  	  V4L2_PIX_FMT_YUYV, 16, "YUV 4:2:2 (YUYV)", },
  	{ MEDIA_BUS_FMT_YUYV8_1_5X8, MEDIA_BUS_FMT_YUYV8_1_5X8,
  	  MEDIA_BUS_FMT_YUYV8_1_5X8, 0,
  	  V4L2_PIX_FMT_NV12, 8, "YUV 4:2:0 (NV12)", },
  };
  
  const struct iss_format_info *
  omap4iss_video_format_info(u32 code)
  {
  	unsigned int i;
  
  	for (i = 0; i < ARRAY_SIZE(formats); ++i) {
  		if (formats[i].code == code)
  			return &formats[i];
  	}
  
  	return NULL;
  }
  
  /*
   * iss_video_mbus_to_pix - Convert v4l2_mbus_framefmt to v4l2_pix_format
   * @video: ISS video instance
   * @mbus: v4l2_mbus_framefmt format (input)
   * @pix: v4l2_pix_format format (output)
   *
   * Fill the output pix structure with information from the input mbus format.
   * The bytesperline and sizeimage fields are computed from the requested bytes
   * per line value in the pix format and information from the video instance.
   *
   * Return the number of padding bytes at end of line.
   */
  static unsigned int iss_video_mbus_to_pix(const struct iss_video *video,
  					  const struct v4l2_mbus_framefmt *mbus,
  					  struct v4l2_pix_format *pix)
  {
  	unsigned int bpl = pix->bytesperline;
  	unsigned int min_bpl;
  	unsigned int i;
  
  	memset(pix, 0, sizeof(*pix));
  	pix->width = mbus->width;
  	pix->height = mbus->height;
  
  	/* Skip the last format in the loop so that it will be selected if no
  	 * match is found.
  	 */
  	for (i = 0; i < ARRAY_SIZE(formats) - 1; ++i) {
  		if (formats[i].code == mbus->code)
  			break;
  	}
  
  	min_bpl = pix->width * ALIGN(formats[i].bpp, 8) / 8;
  
  	/* Clamp the requested bytes per line value. If the maximum bytes per
  	 * line value is zero, the module doesn't support user configurable line
  	 * sizes. Override the requested value with the minimum in that case.
  	 */
  	if (video->bpl_max)
  		bpl = clamp(bpl, min_bpl, video->bpl_max);
  	else
  		bpl = min_bpl;
  
  	if (!video->bpl_zero_padding || bpl != min_bpl)
  		bpl = ALIGN(bpl, video->bpl_alignment);
  
  	pix->pixelformat = formats[i].pixelformat;
  	pix->bytesperline = bpl;
  	pix->sizeimage = pix->bytesperline * pix->height;
  	pix->colorspace = mbus->colorspace;
  	pix->field = mbus->field;
  
  	/* FIXME: Special case for NV12! We should make this nicer... */
  	if (pix->pixelformat == V4L2_PIX_FMT_NV12)
  		pix->sizeimage += (pix->bytesperline * pix->height) / 2;
  
  	return bpl - min_bpl;
  }
  
  static void iss_video_pix_to_mbus(const struct v4l2_pix_format *pix,
  				  struct v4l2_mbus_framefmt *mbus)
  {
  	unsigned int i;
  
  	memset(mbus, 0, sizeof(*mbus));
  	mbus->width = pix->width;
  	mbus->height = pix->height;
  
  	for (i = 0; i < ARRAY_SIZE(formats); ++i) {
  		if (formats[i].pixelformat == pix->pixelformat)
  			break;
  	}
  
  	if (WARN_ON(i == ARRAY_SIZE(formats)))
  		return;
  
  	mbus->code = formats[i].code;
  	mbus->colorspace = pix->colorspace;
  	mbus->field = pix->field;
  }
  
  static struct v4l2_subdev *
  iss_video_remote_subdev(struct iss_video *video, u32 *pad)
  {
  	struct media_pad *remote;
  
  	remote = media_entity_remote_pad(&video->pad);
  
  	if (remote == NULL ||
  	    media_entity_type(remote->entity) != MEDIA_ENT_T_V4L2_SUBDEV)
  		return NULL;
  
  	if (pad)
  		*pad = remote->index;
  
  	return media_entity_to_v4l2_subdev(remote->entity);
  }
  
  /* Return a pointer to the ISS video instance at the far end of the pipeline. */
  static struct iss_video *
  iss_video_far_end(struct iss_video *video)
  {
  	struct media_entity_graph graph;
  	struct media_entity *entity = &video->video.entity;
  	struct media_device *mdev = entity->parent;
  	struct iss_video *far_end = NULL;
  
  	mutex_lock(&mdev->graph_mutex);
  	media_entity_graph_walk_start(&graph, entity);
  
  	while ((entity = media_entity_graph_walk_next(&graph))) {
  		if (entity == &video->video.entity)
  			continue;
  
  		if (media_entity_type(entity) != MEDIA_ENT_T_DEVNODE)
  			continue;
  
  		far_end = to_iss_video(media_entity_to_video_device(entity));
  		if (far_end->type != video->type)
  			break;
  
  		far_end = NULL;
  	}
  
  	mutex_unlock(&mdev->graph_mutex);
  	return far_end;
  }
  
  static int
  __iss_video_get_format(struct iss_video *video,
  		       struct v4l2_mbus_framefmt *format)
  {
  	struct v4l2_subdev_format fmt;
  	struct v4l2_subdev *subdev;
  	u32 pad;
  	int ret;
  
  	subdev = iss_video_remote_subdev(video, &pad);
  	if (subdev == NULL)
  		return -EINVAL;
  
  	memset(&fmt, 0, sizeof(fmt));
  	fmt.pad = pad;
  	fmt.which = V4L2_SUBDEV_FORMAT_ACTIVE;
  
  	mutex_lock(&video->mutex);
  	ret = v4l2_subdev_call(subdev, pad, get_fmt, NULL, &fmt);
  	mutex_unlock(&video->mutex);
  
  	if (ret)
  		return ret;
  
  	*format = fmt.format;
  	return 0;
  }
  
  static int
  iss_video_check_format(struct iss_video *video, struct iss_video_fh *vfh)
  {
  	struct v4l2_mbus_framefmt format;
  	struct v4l2_pix_format pixfmt;
  	int ret;
  
  	ret = __iss_video_get_format(video, &format);
  	if (ret < 0)
  		return ret;
  
  	pixfmt.bytesperline = 0;
  	ret = iss_video_mbus_to_pix(video, &format, &pixfmt);
  
  	if (vfh->format.fmt.pix.pixelformat != pixfmt.pixelformat ||
  	    vfh->format.fmt.pix.height != pixfmt.height ||
  	    vfh->format.fmt.pix.width != pixfmt.width ||
  	    vfh->format.fmt.pix.bytesperline != pixfmt.bytesperline ||
  	    vfh->format.fmt.pix.sizeimage != pixfmt.sizeimage)
  		return -EINVAL;
  
  	return ret;
  }
  
  /* -----------------------------------------------------------------------------
   * Video queue operations
   */
  
  static int iss_video_queue_setup(struct vb2_queue *vq,
  				 const struct v4l2_format *fmt,
  				 unsigned int *count, unsigned int *num_planes,
  				 unsigned int sizes[], void *alloc_ctxs[])
  {
  	struct iss_video_fh *vfh = vb2_get_drv_priv(vq);
  	struct iss_video *video = vfh->video;
  
  	/* Revisit multi-planar support for NV12 */
  	*num_planes = 1;
  
  	sizes[0] = vfh->format.fmt.pix.sizeimage;
  	if (sizes[0] == 0)
  		return -EINVAL;
  
  	alloc_ctxs[0] = video->alloc_ctx;
  
  	*count = min(*count, video->capture_mem / PAGE_ALIGN(sizes[0]));
  
  	return 0;
  }
  
  static void iss_video_buf_cleanup(struct vb2_buffer *vb)
  {
  	struct iss_buffer *buffer = container_of(vb, struct iss_buffer, vb);
  
  	if (buffer->iss_addr)
  		buffer->iss_addr = 0;
  }
  
  static int iss_video_buf_prepare(struct vb2_buffer *vb)
  {
  	struct iss_video_fh *vfh = vb2_get_drv_priv(vb->vb2_queue);
  	struct iss_buffer *buffer = container_of(vb, struct iss_buffer, vb);
  	struct iss_video *video = vfh->video;
  	unsigned long size = vfh->format.fmt.pix.sizeimage;
  	dma_addr_t addr;
  
  	if (vb2_plane_size(vb, 0) < size)
  		return -ENOBUFS;
  
  	addr = vb2_dma_contig_plane_dma_addr(vb, 0);
  	if (!IS_ALIGNED(addr, 32)) {
  		dev_dbg(video->iss->dev,
  			"Buffer address must be aligned to 32 bytes boundary.\n");
  		return -EINVAL;
  	}
  
  	vb2_set_plane_payload(vb, 0, size);
  	buffer->iss_addr = addr;
  	return 0;
  }
  
  static void iss_video_buf_queue(struct vb2_buffer *vb)
  {
  	struct iss_video_fh *vfh = vb2_get_drv_priv(vb->vb2_queue);
  	struct iss_video *video = vfh->video;
  	struct iss_buffer *buffer = container_of(vb, struct iss_buffer, vb);
  	struct iss_pipeline *pipe = to_iss_pipeline(&video->video.entity);
  	unsigned long flags;
  	bool empty;
  
  	spin_lock_irqsave(&video->qlock, flags);
  
  	/* Mark the buffer is faulty and give it back to the queue immediately
  	 * if the video node has registered an error. vb2 will perform the same
  	 * check when preparing the buffer, but that is inherently racy, so we
  	 * need to handle the race condition with an authoritative check here.
  	 */
  	if (unlikely(video->error)) {
  		vb2_buffer_done(vb, VB2_BUF_STATE_ERROR);
  		spin_unlock_irqrestore(&video->qlock, flags);
  		return;
  	}
  
  	empty = list_empty(&video->dmaqueue);
  	list_add_tail(&buffer->list, &video->dmaqueue);
  
  	spin_unlock_irqrestore(&video->qlock, flags);
  
  	if (empty) {
  		enum iss_pipeline_state state;
  		unsigned int start;
  
  		if (video->type == V4L2_BUF_TYPE_VIDEO_CAPTURE)
  			state = ISS_PIPELINE_QUEUE_OUTPUT;
  		else
  			state = ISS_PIPELINE_QUEUE_INPUT;
  
  		spin_lock_irqsave(&pipe->lock, flags);
  		pipe->state |= state;
  		video->ops->queue(video, buffer);
  		video->dmaqueue_flags |= ISS_VIDEO_DMAQUEUE_QUEUED;
  
  		start = iss_pipeline_ready(pipe);
  		if (start)
  			pipe->state |= ISS_PIPELINE_STREAM;
  		spin_unlock_irqrestore(&pipe->lock, flags);
  
  		if (start)
  			omap4iss_pipeline_set_stream(pipe,
  						ISS_PIPELINE_STREAM_SINGLESHOT);
  	}
  }
  
  static const struct vb2_ops iss_video_vb2ops = {
  	.queue_setup	= iss_video_queue_setup,
  	.buf_prepare	= iss_video_buf_prepare,
  	.buf_queue	= iss_video_buf_queue,
  	.buf_cleanup	= iss_video_buf_cleanup,
  };
  
  /*
   * omap4iss_video_buffer_next - Complete the current buffer and return the next
   * @video: ISS video object
   *
   * Remove the current video buffer from the DMA queue and fill its timestamp,
   * field count and state fields before waking up its completion handler.
   *
   * For capture video nodes, the buffer state is set to VB2_BUF_STATE_DONE if no
   * error has been flagged in the pipeline, or to VB2_BUF_STATE_ERROR otherwise.
   *
   * The DMA queue is expected to contain at least one buffer.
   *
   * Return a pointer to the next buffer in the DMA queue, or NULL if the queue is
   * empty.
   */
  struct iss_buffer *omap4iss_video_buffer_next(struct iss_video *video)
  {
  	struct iss_pipeline *pipe = to_iss_pipeline(&video->video.entity);
  	enum iss_pipeline_state state;
  	struct iss_buffer *buf;
  	unsigned long flags;
  	struct timespec ts;
  
  	spin_lock_irqsave(&video->qlock, flags);
  	if (WARN_ON(list_empty(&video->dmaqueue))) {
  		spin_unlock_irqrestore(&video->qlock, flags);
  		return NULL;
  	}
  
  	buf = list_first_entry(&video->dmaqueue, struct iss_buffer,
  			       list);
  	list_del(&buf->list);
  	spin_unlock_irqrestore(&video->qlock, flags);
  
  	ktime_get_ts(&ts);
  	buf->vb.v4l2_buf.timestamp.tv_sec = ts.tv_sec;
  	buf->vb.v4l2_buf.timestamp.tv_usec = ts.tv_nsec / NSEC_PER_USEC;
  
  	/* Do frame number propagation only if this is the output video node.
  	 * Frame number either comes from the CSI receivers or it gets
  	 * incremented here if H3A is not active.
  	 * Note: There is no guarantee that the output buffer will finish
  	 * first, so the input number might lag behind by 1 in some cases.
  	 */
  	if (video == pipe->output && !pipe->do_propagation)
  		buf->vb.v4l2_buf.sequence =
  			atomic_inc_return(&pipe->frame_number);
  	else
  		buf->vb.v4l2_buf.sequence = atomic_read(&pipe->frame_number);
  
  	vb2_buffer_done(&buf->vb, pipe->error ?
  			VB2_BUF_STATE_ERROR : VB2_BUF_STATE_DONE);
  	pipe->error = false;
  
  	spin_lock_irqsave(&video->qlock, flags);
  	if (list_empty(&video->dmaqueue)) {
  		spin_unlock_irqrestore(&video->qlock, flags);
  		if (video->type == V4L2_BUF_TYPE_VIDEO_CAPTURE)
  			state = ISS_PIPELINE_QUEUE_OUTPUT
  			      | ISS_PIPELINE_STREAM;
  		else
  			state = ISS_PIPELINE_QUEUE_INPUT
  			      | ISS_PIPELINE_STREAM;
  
  		spin_lock_irqsave(&pipe->lock, flags);
  		pipe->state &= ~state;
  		if (video->pipe.stream_state == ISS_PIPELINE_STREAM_CONTINUOUS)
  			video->dmaqueue_flags |= ISS_VIDEO_DMAQUEUE_UNDERRUN;
  		spin_unlock_irqrestore(&pipe->lock, flags);
  		return NULL;
  	}
  
  	if (video->type == V4L2_BUF_TYPE_VIDEO_CAPTURE && pipe->input != NULL) {
  		spin_lock(&pipe->lock);
  		pipe->state &= ~ISS_PIPELINE_STREAM;
  		spin_unlock(&pipe->lock);
  	}
  
  	buf = list_first_entry(&video->dmaqueue, struct iss_buffer,
  			       list);
  	spin_unlock_irqrestore(&video->qlock, flags);
  	buf->vb.state = VB2_BUF_STATE_ACTIVE;
  	return buf;
  }
  
  /*
   * omap4iss_video_cancel_stream - Cancel stream on a video node
   * @video: ISS video object
   *
   * Cancelling a stream mark all buffers on the video node as erroneous and makes
   * sure no new buffer can be queued.
   */
  void omap4iss_video_cancel_stream(struct iss_video *video)
  {
  	unsigned long flags;
  
  	spin_lock_irqsave(&video->qlock, flags);
  
  	while (!list_empty(&video->dmaqueue)) {
  		struct iss_buffer *buf;
  
  		buf = list_first_entry(&video->dmaqueue, struct iss_buffer,
  				       list);
  		list_del(&buf->list);
  		vb2_buffer_done(&buf->vb, VB2_BUF_STATE_ERROR);
  	}
  
  	vb2_queue_error(video->queue);
  	video->error = true;
  
  	spin_unlock_irqrestore(&video->qlock, flags);
  }
  
  /* -----------------------------------------------------------------------------
   * V4L2 ioctls
   */
  
  static int
  iss_video_querycap(struct file *file, void *fh, struct v4l2_capability *cap)
  {
  	struct iss_video *video = video_drvdata(file);
  
  	strlcpy(cap->driver, ISS_VIDEO_DRIVER_NAME, sizeof(cap->driver));
  	strlcpy(cap->card, video->video.name, sizeof(cap->card));
  	strlcpy(cap->bus_info, "media", sizeof(cap->bus_info));
  
  	if (video->type == V4L2_BUF_TYPE_VIDEO_CAPTURE)
  		cap->device_caps = V4L2_CAP_VIDEO_CAPTURE | V4L2_CAP_STREAMING;
  	else
  		cap->device_caps = V4L2_CAP_VIDEO_OUTPUT | V4L2_CAP_STREAMING;
  
  	cap->capabilities = V4L2_CAP_DEVICE_CAPS | V4L2_CAP_STREAMING
  			  | V4L2_CAP_VIDEO_CAPTURE | V4L2_CAP_VIDEO_OUTPUT;
  
  	return 0;
  }
  
  static int
  iss_video_enum_format(struct file *file, void *fh, struct v4l2_fmtdesc *f)
  {
  	struct iss_video *video = video_drvdata(file);
  	struct v4l2_mbus_framefmt format;
  	unsigned int index = f->index;
  	unsigned int i;
  	int ret;
  
  	if (f->type != video->type)
  		return -EINVAL;
  
  	ret = __iss_video_get_format(video, &format);
  	if (ret < 0)
  		return ret;
  
  	for (i = 0; i < ARRAY_SIZE(formats); ++i) {
  		const struct iss_format_info *info = &formats[i];
  
  		if (format.code != info->code)
  			continue;
  
  		if (index == 0) {
  			f->pixelformat = info->pixelformat;
  			strlcpy(f->description, info->description,
  				sizeof(f->description));
  			return 0;
  		}
  
  		index--;
  	}
  
  	return -EINVAL;
  }
  
  static int
  iss_video_get_format(struct file *file, void *fh, struct v4l2_format *format)
  {
  	struct iss_video_fh *vfh = to_iss_video_fh(fh);
  	struct iss_video *video = video_drvdata(file);
  
  	if (format->type != video->type)
  		return -EINVAL;
  
  	mutex_lock(&video->mutex);
  	*format = vfh->format;
  	mutex_unlock(&video->mutex);
  
  	return 0;
  }
  
  static int
  iss_video_set_format(struct file *file, void *fh, struct v4l2_format *format)
  {
  	struct iss_video_fh *vfh = to_iss_video_fh(fh);
  	struct iss_video *video = video_drvdata(file);
  	struct v4l2_mbus_framefmt fmt;
  
  	if (format->type != video->type)
  		return -EINVAL;
  
  	mutex_lock(&video->mutex);
  
  	/* Fill the bytesperline and sizeimage fields by converting to media bus
  	 * format and back to pixel format.
  	 */
  	iss_video_pix_to_mbus(&format->fmt.pix, &fmt);
  	iss_video_mbus_to_pix(video, &fmt, &format->fmt.pix);
  
  	vfh->format = *format;
  
  	mutex_unlock(&video->mutex);
  	return 0;
  }
  
  static int
  iss_video_try_format(struct file *file, void *fh, struct v4l2_format *format)
  {
  	struct iss_video *video = video_drvdata(file);
  	struct v4l2_subdev_format fmt;
  	struct v4l2_subdev *subdev;
  	u32 pad;
  	int ret;
  
  	if (format->type != video->type)
  		return -EINVAL;
  
  	subdev = iss_video_remote_subdev(video, &pad);
  	if (subdev == NULL)
  		return -EINVAL;
  
  	iss_video_pix_to_mbus(&format->fmt.pix, &fmt.format);
  
  	fmt.pad = pad;
  	fmt.which = V4L2_SUBDEV_FORMAT_ACTIVE;
  	ret = v4l2_subdev_call(subdev, pad, get_fmt, NULL, &fmt);
  	if (ret)
  		return ret;
  
  	iss_video_mbus_to_pix(video, &fmt.format, &format->fmt.pix);
  	return 0;
  }
  
  static int
  iss_video_cropcap(struct file *file, void *fh, struct v4l2_cropcap *cropcap)
  {
  	struct iss_video *video = video_drvdata(file);
  	struct v4l2_subdev *subdev;
  	int ret;
  
  	subdev = iss_video_remote_subdev(video, NULL);
  	if (subdev == NULL)
  		return -EINVAL;
  
  	mutex_lock(&video->mutex);
  	ret = v4l2_subdev_call(subdev, video, cropcap, cropcap);
  	mutex_unlock(&video->mutex);
  
  	return ret == -ENOIOCTLCMD ? -ENOTTY : ret;
  }
  
  static int
  iss_video_get_crop(struct file *file, void *fh, struct v4l2_crop *crop)
  {
  	struct iss_video *video = video_drvdata(file);
  	struct v4l2_subdev_format format;
  	struct v4l2_subdev *subdev;
  	u32 pad;
  	int ret;
  
  	subdev = iss_video_remote_subdev(video, &pad);
  	if (subdev == NULL)
  		return -EINVAL;
  
  	/* Try the get crop operation first and fallback to get format if not
  	 * implemented.
  	 */
  	ret = v4l2_subdev_call(subdev, video, g_crop, crop);
  	if (ret != -ENOIOCTLCMD)
  		return ret;
  
  	format.pad = pad;
  	format.which = V4L2_SUBDEV_FORMAT_ACTIVE;
  	ret = v4l2_subdev_call(subdev, pad, get_fmt, NULL, &format);
  	if (ret < 0)
  		return ret == -ENOIOCTLCMD ? -ENOTTY : ret;
  
  	crop->c.left = 0;
  	crop->c.top = 0;
  	crop->c.width = format.format.width;
  	crop->c.height = format.format.height;
  
  	return 0;
  }
  
  static int
  iss_video_set_crop(struct file *file, void *fh, const struct v4l2_crop *crop)
  {
  	struct iss_video *video = video_drvdata(file);
  	struct v4l2_subdev *subdev;
  	int ret;
  
  	subdev = iss_video_remote_subdev(video, NULL);
  	if (subdev == NULL)
  		return -EINVAL;
  
  	mutex_lock(&video->mutex);
  	ret = v4l2_subdev_call(subdev, video, s_crop, crop);
  	mutex_unlock(&video->mutex);
  
  	return ret == -ENOIOCTLCMD ? -ENOTTY : ret;
  }
  
  static int
  iss_video_get_param(struct file *file, void *fh, struct v4l2_streamparm *a)
  {
  	struct iss_video_fh *vfh = to_iss_video_fh(fh);
  	struct iss_video *video = video_drvdata(file);
  
  	if (video->type != V4L2_BUF_TYPE_VIDEO_OUTPUT ||
  	    video->type != a->type)
  		return -EINVAL;
  
  	memset(a, 0, sizeof(*a));
  	a->type = V4L2_BUF_TYPE_VIDEO_OUTPUT;
  	a->parm.output.capability = V4L2_CAP_TIMEPERFRAME;
  	a->parm.output.timeperframe = vfh->timeperframe;
  
  	return 0;
  }
  
  static int
  iss_video_set_param(struct file *file, void *fh, struct v4l2_streamparm *a)
  {
  	struct iss_video_fh *vfh = to_iss_video_fh(fh);
  	struct iss_video *video = video_drvdata(file);
  
  	if (video->type != V4L2_BUF_TYPE_VIDEO_OUTPUT ||
  	    video->type != a->type)
  		return -EINVAL;
  
  	if (a->parm.output.timeperframe.denominator == 0)
  		a->parm.output.timeperframe.denominator = 1;
  
  	vfh->timeperframe = a->parm.output.timeperframe;
  
  	return 0;
  }
  
  static int
  iss_video_reqbufs(struct file *file, void *fh, struct v4l2_requestbuffers *rb)
  {
  	struct iss_video_fh *vfh = to_iss_video_fh(fh);
  
  	return vb2_reqbufs(&vfh->queue, rb);
  }
  
  static int
  iss_video_querybuf(struct file *file, void *fh, struct v4l2_buffer *b)
  {
  	struct iss_video_fh *vfh = to_iss_video_fh(fh);
  
  	return vb2_querybuf(&vfh->queue, b);
  }
  
  static int
  iss_video_qbuf(struct file *file, void *fh, struct v4l2_buffer *b)
  {
  	struct iss_video_fh *vfh = to_iss_video_fh(fh);
  
  	return vb2_qbuf(&vfh->queue, b);
  }
  
  static int
  iss_video_dqbuf(struct file *file, void *fh, struct v4l2_buffer *b)
  {
  	struct iss_video_fh *vfh = to_iss_video_fh(fh);
  
  	return vb2_dqbuf(&vfh->queue, b, file->f_flags & O_NONBLOCK);
  }
  
  /*
   * Stream management
   *
   * Every ISS pipeline has a single input and a single output. The input can be
   * either a sensor or a video node. The output is always a video node.
   *
   * As every pipeline has an output video node, the ISS video objects at the
   * pipeline output stores the pipeline state. It tracks the streaming state of
   * both the input and output, as well as the availability of buffers.
   *
   * In sensor-to-memory mode, frames are always available at the pipeline input.
   * Starting the sensor usually requires I2C transfers and must be done in
   * interruptible context. The pipeline is started and stopped synchronously
   * to the stream on/off commands. All modules in the pipeline will get their
   * subdev set stream handler called. The module at the end of the pipeline must
   * delay starting the hardware until buffers are available at its output.
   *
   * In memory-to-memory mode, starting/stopping the stream requires
   * synchronization between the input and output. ISS modules can't be stopped
   * in the middle of a frame, and at least some of the modules seem to become
   * busy as soon as they're started, even if they don't receive a frame start
   * event. For that reason frames need to be processed in single-shot mode. The
   * driver needs to wait until a frame is completely processed and written to
   * memory before restarting the pipeline for the next frame. Pipelined
   * processing might be possible but requires more testing.
   *
   * Stream start must be delayed until buffers are available at both the input
   * and output. The pipeline must be started in the videobuf queue callback with
   * the buffers queue spinlock held. The modules subdev set stream operation must
   * not sleep.
   */
  static int
  iss_video_streamon(struct file *file, void *fh, enum v4l2_buf_type type)
  {
  	struct iss_video_fh *vfh = to_iss_video_fh(fh);
  	struct iss_video *video = video_drvdata(file);
  	struct media_entity_graph graph;
  	struct media_entity *entity;
  	enum iss_pipeline_state state;
  	struct iss_pipeline *pipe;
  	struct iss_video *far_end;
  	unsigned long flags;
  	int ret;
  
  	if (type != video->type)
  		return -EINVAL;
  
  	mutex_lock(&video->stream_lock);
  
  	/* Start streaming on the pipeline. No link touching an entity in the
  	 * pipeline can be activated or deactivated once streaming is started.
  	 */
  	pipe = video->video.entity.pipe
  	     ? to_iss_pipeline(&video->video.entity) : &video->pipe;
  	pipe->external = NULL;
  	pipe->external_rate = 0;
  	pipe->external_bpp = 0;
  	pipe->entities = 0;
  
  	if (video->iss->pdata->set_constraints)
  		video->iss->pdata->set_constraints(video->iss, true);
  
  	ret = media_entity_pipeline_start(&video->video.entity, &pipe->pipe);
  	if (ret < 0)
  		goto err_media_entity_pipeline_start;
  
  	entity = &video->video.entity;
  	media_entity_graph_walk_start(&graph, entity);
  	while ((entity = media_entity_graph_walk_next(&graph)))
  		pipe->entities |= 1 << entity->id;
  
  	/* Verify that the currently configured format matches the output of
  	 * the connected subdev.
  	 */
  	ret = iss_video_check_format(video, vfh);
  	if (ret < 0)
  		goto err_iss_video_check_format;
  
  	video->bpl_padding = ret;
  	video->bpl_value = vfh->format.fmt.pix.bytesperline;
  
  	/* Find the ISS video node connected at the far end of the pipeline and
  	 * update the pipeline.
  	 */
  	far_end = iss_video_far_end(video);
  
  	if (video->type == V4L2_BUF_TYPE_VIDEO_CAPTURE) {
  		state = ISS_PIPELINE_STREAM_OUTPUT | ISS_PIPELINE_IDLE_OUTPUT;
  		pipe->input = far_end;
  		pipe->output = video;
  	} else {
  		if (far_end == NULL) {
  			ret = -EPIPE;
  			goto err_iss_video_check_format;
  		}
  
  		state = ISS_PIPELINE_STREAM_INPUT | ISS_PIPELINE_IDLE_INPUT;
  		pipe->input = video;
  		pipe->output = far_end;
  	}
  
  	spin_lock_irqsave(&pipe->lock, flags);
  	pipe->state &= ~ISS_PIPELINE_STREAM;
  	pipe->state |= state;
  	spin_unlock_irqrestore(&pipe->lock, flags);
  
  	/* Set the maximum time per frame as the value requested by userspace.
  	 * This is a soft limit that can be overridden if the hardware doesn't
  	 * support the request limit.
  	 */
  	if (video->type == V4L2_BUF_TYPE_VIDEO_OUTPUT)
  		pipe->max_timeperframe = vfh->timeperframe;
  
  	video->queue = &vfh->queue;
  	INIT_LIST_HEAD(&video->dmaqueue);
  	video->error = false;
  	atomic_set(&pipe->frame_number, -1);
  
  	ret = vb2_streamon(&vfh->queue, type);
  	if (ret < 0)
  		goto err_iss_video_check_format;
  
  	/* In sensor-to-memory mode, the stream can be started synchronously
  	 * to the stream on command. In memory-to-memory mode, it will be
  	 * started when buffers are queued on both the input and output.
  	 */
  	if (pipe->input == NULL) {
  		unsigned long flags;
  
  		ret = omap4iss_pipeline_set_stream(pipe,
  					      ISS_PIPELINE_STREAM_CONTINUOUS);
  		if (ret < 0)
  			goto err_omap4iss_set_stream;
  		spin_lock_irqsave(&video->qlock, flags);
  		if (list_empty(&video->dmaqueue))
  			video->dmaqueue_flags |= ISS_VIDEO_DMAQUEUE_UNDERRUN;
  		spin_unlock_irqrestore(&video->qlock, flags);
  	}
  
  	mutex_unlock(&video->stream_lock);
  	return 0;
  
  err_omap4iss_set_stream:
  	vb2_streamoff(&vfh->queue, type);
  err_iss_video_check_format:
  	media_entity_pipeline_stop(&video->video.entity);
  err_media_entity_pipeline_start:
  	if (video->iss->pdata->set_constraints)
  		video->iss->pdata->set_constraints(video->iss, false);
  	video->queue = NULL;
  
  	mutex_unlock(&video->stream_lock);
  	return ret;
  }
  
  static int
  iss_video_streamoff(struct file *file, void *fh, enum v4l2_buf_type type)
  {
  	struct iss_video_fh *vfh = to_iss_video_fh(fh);
  	struct iss_video *video = video_drvdata(file);
  	struct iss_pipeline *pipe = to_iss_pipeline(&video->video.entity);
  	enum iss_pipeline_state state;
  	unsigned long flags;
  
  	if (type != video->type)
  		return -EINVAL;
  
  	mutex_lock(&video->stream_lock);
  
  	if (!vb2_is_streaming(&vfh->queue))
  		goto done;
  
  	/* Update the pipeline state. */
  	if (video->type == V4L2_BUF_TYPE_VIDEO_CAPTURE)
  		state = ISS_PIPELINE_STREAM_OUTPUT
  		      | ISS_PIPELINE_QUEUE_OUTPUT;
  	else
  		state = ISS_PIPELINE_STREAM_INPUT
  		      | ISS_PIPELINE_QUEUE_INPUT;
  
  	spin_lock_irqsave(&pipe->lock, flags);
  	pipe->state &= ~state;
  	spin_unlock_irqrestore(&pipe->lock, flags);
  
  	/* Stop the stream. */
  	omap4iss_pipeline_set_stream(pipe, ISS_PIPELINE_STREAM_STOPPED);
  	vb2_streamoff(&vfh->queue, type);
  	video->queue = NULL;
  
  	if (video->iss->pdata->set_constraints)
  		video->iss->pdata->set_constraints(video->iss, false);
  	media_entity_pipeline_stop(&video->video.entity);
  
  done:
  	mutex_unlock(&video->stream_lock);
  	return 0;
  }
  
  static int
  iss_video_enum_input(struct file *file, void *fh, struct v4l2_input *input)
  {
  	if (input->index > 0)
  		return -EINVAL;
  
  	strlcpy(input->name, "camera", sizeof(input->name));
  	input->type = V4L2_INPUT_TYPE_CAMERA;
  
  	return 0;
  }
  
  static int
  iss_video_g_input(struct file *file, void *fh, unsigned int *input)
  {
  	*input = 0;
  
  	return 0;
  }
  
  static int
  iss_video_s_input(struct file *file, void *fh, unsigned int input)
  {
  	return input == 0 ? 0 : -EINVAL;
  }
  
  static const struct v4l2_ioctl_ops iss_video_ioctl_ops = {
  	.vidioc_querycap		= iss_video_querycap,
  	.vidioc_enum_fmt_vid_cap        = iss_video_enum_format,
  	.vidioc_g_fmt_vid_cap		= iss_video_get_format,
  	.vidioc_s_fmt_vid_cap		= iss_video_set_format,
  	.vidioc_try_fmt_vid_cap		= iss_video_try_format,
  	.vidioc_g_fmt_vid_out		= iss_video_get_format,
  	.vidioc_s_fmt_vid_out		= iss_video_set_format,
  	.vidioc_try_fmt_vid_out		= iss_video_try_format,
  	.vidioc_cropcap			= iss_video_cropcap,
  	.vidioc_g_crop			= iss_video_get_crop,
  	.vidioc_s_crop			= iss_video_set_crop,
  	.vidioc_g_parm			= iss_video_get_param,
  	.vidioc_s_parm			= iss_video_set_param,
  	.vidioc_reqbufs			= iss_video_reqbufs,
  	.vidioc_querybuf		= iss_video_querybuf,
  	.vidioc_qbuf			= iss_video_qbuf,
  	.vidioc_dqbuf			= iss_video_dqbuf,
  	.vidioc_streamon		= iss_video_streamon,
  	.vidioc_streamoff		= iss_video_streamoff,
  	.vidioc_enum_input		= iss_video_enum_input,
  	.vidioc_g_input			= iss_video_g_input,
  	.vidioc_s_input			= iss_video_s_input,
  };
  
  /* -----------------------------------------------------------------------------
   * V4L2 file operations
   */
  
  static int iss_video_open(struct file *file)
  {
  	struct iss_video *video = video_drvdata(file);
  	struct iss_video_fh *handle;
  	struct vb2_queue *q;
  	int ret = 0;
  
  	handle = kzalloc(sizeof(*handle), GFP_KERNEL);
  	if (handle == NULL)
  		return -ENOMEM;
  
  	video->video.debug = debug;
  
  	v4l2_fh_init(&handle->vfh, &video->video);
  	v4l2_fh_add(&handle->vfh);
  
  	/* If this is the first user, initialise the pipeline. */
  	if (omap4iss_get(video->iss) == NULL) {
  		ret = -EBUSY;
  		goto done;
  	}
  
  	ret = omap4iss_pipeline_pm_use(&video->video.entity, 1);
  	if (ret < 0) {
  		omap4iss_put(video->iss);
  		goto done;
  	}
  
  	video->alloc_ctx = vb2_dma_contig_init_ctx(video->iss->dev);
  	if (IS_ERR(video->alloc_ctx)) {
  		ret = PTR_ERR(video->alloc_ctx);
  		omap4iss_put(video->iss);
  		goto done;
  	}
  
  	q = &handle->queue;
  
  	q->type = video->type;
  	q->io_modes = VB2_MMAP;
  	q->drv_priv = handle;
  	q->ops = &iss_video_vb2ops;
  	q->mem_ops = &vb2_dma_contig_memops;
  	q->buf_struct_size = sizeof(struct iss_buffer);
  	q->timestamp_flags = V4L2_BUF_FLAG_TIMESTAMP_MONOTONIC;
  
  	ret = vb2_queue_init(q);
  	if (ret) {
  		omap4iss_put(video->iss);
  		goto done;
  	}
  
  	memset(&handle->format, 0, sizeof(handle->format));
  	handle->format.type = video->type;
  	handle->timeperframe.denominator = 1;
  
  	handle->video = video;
  	file->private_data = &handle->vfh;
  
  done:
  	if (ret < 0) {
  		v4l2_fh_del(&handle->vfh);
  		kfree(handle);
  	}
  
  	return ret;
  }
  
  static int iss_video_release(struct file *file)
  {
  	struct iss_video *video = video_drvdata(file);
  	struct v4l2_fh *vfh = file->private_data;
  	struct iss_video_fh *handle = to_iss_video_fh(vfh);
  
  	/* Disable streaming and free the buffers queue resources. */
  	iss_video_streamoff(file, vfh, video->type);
  
  	omap4iss_pipeline_pm_use(&video->video.entity, 0);
  
  	/* Release the videobuf2 queue */
  	vb2_queue_release(&handle->queue);
  
  	/* Release the file handle. */
  	v4l2_fh_del(vfh);
  	kfree(handle);
  	file->private_data = NULL;
  
  	omap4iss_put(video->iss);
  
  	return 0;
  }
  
  static unsigned int iss_video_poll(struct file *file, poll_table *wait)
  {
  	struct iss_video_fh *vfh = to_iss_video_fh(file->private_data);
  
  	return vb2_poll(&vfh->queue, file, wait);
  }
  
  static int iss_video_mmap(struct file *file, struct vm_area_struct *vma)
  {
  	struct iss_video_fh *vfh = to_iss_video_fh(file->private_data);
  
  	return vb2_mmap(&vfh->queue, vma);
  }
  
  static struct v4l2_file_operations iss_video_fops = {
  	.owner = THIS_MODULE,
  	.unlocked_ioctl = video_ioctl2,
  	.open = iss_video_open,
  	.release = iss_video_release,
  	.poll = iss_video_poll,
  	.mmap = iss_video_mmap,
  };
  
  /* -----------------------------------------------------------------------------
   * ISS video core
   */
  
  static const struct iss_video_operations iss_video_dummy_ops = {
  };
  
  int omap4iss_video_init(struct iss_video *video, const char *name)
  {
  	const char *direction;
  	int ret;
  
  	switch (video->type) {
  	case V4L2_BUF_TYPE_VIDEO_CAPTURE:
  		direction = "output";
  		video->pad.flags = MEDIA_PAD_FL_SINK;
  		break;
  	case V4L2_BUF_TYPE_VIDEO_OUTPUT:
  		direction = "input";
  		video->pad.flags = MEDIA_PAD_FL_SOURCE;
  		break;
  
  	default:
  		return -EINVAL;
  	}
  
  	ret = media_entity_init(&video->video.entity, 1, &video->pad, 0);
  	if (ret < 0)
  		return ret;
  
  	spin_lock_init(&video->qlock);
  	mutex_init(&video->mutex);
  	atomic_set(&video->active, 0);
  
  	spin_lock_init(&video->pipe.lock);
  	mutex_init(&video->stream_lock);
  
  	/* Initialize the video device. */
  	if (video->ops == NULL)
  		video->ops = &iss_video_dummy_ops;
  
  	video->video.fops = &iss_video_fops;
  	snprintf(video->video.name, sizeof(video->video.name),
  		 "OMAP4 ISS %s %s", name, direction);
  	video->video.vfl_type = VFL_TYPE_GRABBER;
  	video->video.release = video_device_release_empty;
  	video->video.ioctl_ops = &iss_video_ioctl_ops;
  	video->pipe.stream_state = ISS_PIPELINE_STREAM_STOPPED;
  
  	video_set_drvdata(&video->video, video);
  
  	return 0;
  }
  
  void omap4iss_video_cleanup(struct iss_video *video)
  {
  	media_entity_cleanup(&video->video.entity);
  	mutex_destroy(&video->stream_lock);
  	mutex_destroy(&video->mutex);
  }
  
  int omap4iss_video_register(struct iss_video *video, struct v4l2_device *vdev)
  {
  	int ret;
  
  	video->video.v4l2_dev = vdev;
  
  	ret = video_register_device(&video->video, VFL_TYPE_GRABBER, -1);
  	if (ret < 0)
  		dev_err(video->iss->dev,
  			"%s: could not register video device (%d)\n",
  			__func__, ret);
  
  	return ret;
  }
  
  void omap4iss_video_unregister(struct iss_video *video)
  {
  	video_unregister_device(&video->video);
  }
  